Scratch brushing apparatus for cleaning portions of circular articles



Aug. 30, 1949. .1. R. MARCUS x-:T AL

SCRATCH BRUSHING APPARATUS FOR 2,480,489 CLEANING PoRTIoNs 0F CIRCULAR ARTICLES 4 Sheets-Sheet 1 Filed July 3, 1946 J; A. MARCUS wu-L Arm/PNB Aug. 30, 1949. .1. R. MARCUS ET AL SCRATCH BRUSHING APPARATUS FOR CLEANING PORTIONS OF CIRCULAR ARTICLES Filed July 3, 1946 Aug. 30, 1949. f J. R. ARcus Er Al. 2,480,439

SCRATCH BRUSH APPARATUS FR CLEANING PORTIONS 0F CIRCULAR ARTICLES 4 Sheets-Sheet 3 Filed July 3, 1946 Mfg/.Mmes 9/ g5 J. R. MARCUS L. E14/AMER Arro/r/vfr Aug. 30, 1949. J. R. MARCUS ET Al. 2,480,489

SCRATC RUSHING APPARATUS FOR CLEANING P IONS 0F CIRCULAR ARTICLES 4 Sheets-Sheet 4 Filed July 3, 1946 spgm N' F//O 'm M Patented Aug. 30, 1949 SCRATCH BRUSHING APPARATUS FOR CLEANING PORTIONS OF CIRCULAR ARTICLES Jerome R. Marcus, Chicago, and Lawrence B.

Walter, Elmhurst, Ill.,

Electric Company,

N. Y., a corporation 3 Claims.

assignors to Western Incorporated, New York,

of New York Application July 3, 1946, Serial No. 681,214

This invention relates to scratch brushing apl paratus and more particularly to a rotary brush type of apparatus for cleaning portions of the resistance elements of circular potentiometer units.

One type of potentiometer unit is made by winding insulated wire on nat strips of insulation to form resistance elements known as potentiometer cards which then must be scratchbrushed along one edge to remove the insulation from the wire. The flat resistance elements, together with insulation strips and slip ring strips, are bent into annular shape and cemented together in annular grooves in one side of a housing so thatfthe cleaned edges of the resistance elements and the edges of the slip rings project from the face of the housing in concentric spaced relation to each other and are adapted to be engaged by sliding contact members. In cementing and assembling the parts together, some of the cement used may get on the cleaned edges of the resistance elements and it is necessary to reclean the projecting edges of the resistance elements Without damaging or defacing the slip rings thereon.

It is an object of simple and effective cuate articles.

In one embodiment of the invention, there is provided a plurality of stations at each of which there is a plate for supporting a circular potentiometer unit and a spindle extending upwardly from the plate about which the potentiometer unit may be manually rotated. Grooves are formed in each of the plates concentric with the spindles for receiving the edges of the annular resistance elements, which comprise coated wire wound on thin strips of insulation and which project from the face of the potentiometer unit. At each station, a rotary scratch brus extends upwardly into a recess in the underside of each plate, which recess intersects a groove in the upper side of the supporting plate to form a slot through which the rotary scratch brush may engage the wire on the edge of the resistance elements and clean foreign matter therefrom. The brushes and the slots through which they engage the edges of the resistance elements are spaced relative to the spindles at the various stations so that the brushes engage a different one of the this invention to provide a apparatus for cleaning ar- Vresistance elements of the potentiometer unit at the different stations whereby a potentiometer unit may be positioned successively on each of the spindles and rotated through one or more revolutions to clean the resistance Wires .on the edge of each of the potentiometer cards thereon.

A more complete understanding of the invention may be had by reference to the following detailed description thereof and the accompanying drawings illustrating a preferred embodiment of the invention wherein Y Fig. 1 is a plan view of the apparatus showing four stations at each of which a potentiometer unit may be partially cleaned and showing, in dotted lines, the rotary scratch brushes and the means for driving. them;

Fig. 2 is a vertical sectional view of a portion of the apparatus, with parts broken away, taken on the line 2 2 of Fig. 1 in the direction of the arrows and showing a potentiometer unit in dot and dash lines at each ofthe stations of the apparatus;

Figs. 3, 4, 5 and 6 are vertical sectional views through portions of the apparatus taken on the lines 3 3, 4 4, 5 5 and 6 6, respectively, of Fig. 1 in the direction of the arrows and showing a portion of a potentiometer unit on the supporting member and the rotary brushes engaging the edges of different potentiometer cards at each of the different stations;

Fig. '7 is an enlarged fragmentary vertical sectional view through the potentiometer unit showing a potentiometer card, insulating strips, and a slip ring mounted in an annular groove of the potentiometer unit;

Fig. 8 is an enlarged fragmentary plan view of one station of the apparatus shown in Fig. 1, showing the means for supporting and positioning a potentiometer unit thereon;

Fig. 9 is a vertical sectional view of a portion of the apparatus taken on the line 9 9 of Fig. a in the direction of the arrows, showing the potentiometer unit supporting and positioning means and the rotary scratch brush and showing a potentiometer unit in dot and dash lines;

Fig. 10 is a vertical sectional view of a portion of the apparatus taken on the line lU-I 0 of Fig. 1 and showing a potentiometer unit in position thereon;

Fig. 11 is an enlarged face view of a portion of the potentiometer unit; and

Fig. 12 is an enlarged fragmentary view of a potentiometer card showing the resistance wire wound thereon. y

Referring to the drawings, the apparatus shown is for cleaning a circular potentiometer unit of the type illustrated in Figs. 3, 7, 10, 11 and 12. The potentiometer unit I5 comprises a cylindri- -cal housing I6 having a central aperture l1 therethrough and a plurality of concentric annular grooves 26, 2|, 22 and 23 formed in one side thereof in which are mounted the resistance elements or potentiometer cards 25, 26, 21 and 28, respectively. As shown particularly in Figs. 'I and 12, each resistance element comprises a coated wire '36 'wound on a flat strip or card of insulation 3| with the turns of wire in spaced relation to each other. The resistance elements are processed in a scratch -brushing operation to remove the insulation from the wire along one edge of the potentiometer cards prior to their as sembly in the unit. The resistance elements 25, 25, 21 and 28 are mounted in the grooves of the potentiometer unit with the cleaned-edges thereof projecting a predetermined distance -frcrn'the face of the potentiometer unit and with insulating cards 35 and 36 positioned cn-eachaideth'ereof. Metallic slip rings 39 mounted in each of the grooves of the potentiometer unit extend beyond the face of the potentiometer unit, each with the edge thereof in a predeterminedspaced relation to the edge of the potentiometer card associated therewith and the rings 39 are held in position in the `grooves by corrugated metal spacers 4Q (Figs. '7 and 11) interposed between the slip rings 39 and the adjacent insulating cards 35.

Metallic contact members (not shown) are adapted to engage the windings 38 of the van ious resistance units 25, 26, 21 and 2B and the respective slip rings 39 associated therewith. in the assembling of these parts, a cement is used to secure the resistance elements, the insulating cards 35 and 36, the slips rings 39 and 'the spacers 4|) in proper position in the grooves in the poten-- tiometer unit. Because some of the cement may inadvertently be applied on the cleaned edges of the potentiometer cards, it is necessary to reclean the edges thereof so that the sliding contact members may make metallic contact between each of the various points Aof the resistance elements at the extending ends of the cards and the slip rings 39 associated therewith.

The cleaning apparatus comprises a housing 44, in the forward portion of which there is provided a plurality of stations 45, 45, 41 and 48, and at which stations the resistance'elements 25, 26, 21 and 28, respectively,` are adapted to be cleaned. A plate 49 (Figs. l` and 10) secured to end walls 50 and 5| of the housing 44, forms a top for the rear portion of the apparatus adjacent the stations 45-48. From the end walls 55 and of the housing 44 extend horizontal attaching flanges 52 and 53 (Figs. l and 2), which enga-ge the underneath side of a table or bench top 54, and are secured thereto by bolts 55 so that the top of the apparatus fits in a recess in the table 54 and is substantially flush therewith. Formed integral with, as by welding, and ex tending between theA end walls 5|) and 5| of the housing are a rear wall 56 (Fig. 1), a bottom wall 51V (Fig. 10), an oblique front wall 58 and a vertical front wall 59'. A horizontal shelf 6|).` is formed by an angle member 6| welded to the oblique wall 58 (Fig. 10) and' the end walls 5|) and 5| (Fig. 2). Extending rearwardly from' the upper portion of the frontwall 59` are a plurality of horizontal supports or plates 64, 65, 56, 51 and 5B (Figs. 1, 2 and 10) the plates 64 and 68 being attached tov the end walls 5B and 5|', respectively. At their rear ends, the supporting plates 65', 66 and B1 areA supported by vertically' extending integrally formed supporting members 13"--13 (Fig. 2), which project upwardly from and are welded to the shelf 6U'.

Mounted on each of the plates 65, 66, 61 and 68 is a bracket 10, apertured to receive a pivot pin 1|. The ends of the pivot pins 1| extend beyond the brackets 16 and engage in apertures 12-12 (Fig. 8) 'inlugs 114-14 4forrie'd on lthe ends of a plurality of adjustable supporting plates 15, 16, 11 and 18 at the stations 45, 46, 41 and 48, refspectively. The supporting plates 15, 16, 11 and 18, at one end, are pivotally supported on the pivot pins 1| (Figs. 8 and 9) and at their opposite end's "'a'r'e 'provided with apertures 3| forming shoulders B2, which are engageable with the heads 83 of machine screws 84. The machine screws 84 are adjustably mounted in threaded apertures `|15 in the supporting members 64, 65,

66 and 61 and support each of the adjustable plate members in an adjusted position. Apertures B1 having shoulders 88 are provided in the supporting plates 15, 16, 11 and 18 adjacent the apertures 8| and are adapted to 4receive the needs 'es ci clamping screws et, which engage threaded` 4aperturesUSl-l i'n the V"supporting "ri'eir- :bers`64j6`5y66 and 61. I u

Each of the supporting plates 15, 16, 11 and .1 8 is provided with a positioning spindle or rod r92, 'which is secured in 'an aperture 93 in the 'plate and extends upwardly from the 'upper surface of the plates for positioning Ja vpotentioxi'ieter u iii', in a predetermined position on. the siipp'oi'ting plate, 'as indicated in dot and dash lines in Figs. 2, '8 'and 9. Formed in the upper Yside of the plates 15,16, 11 and is are annular grooves et, st, si and 98, respectively, of vaii'ous Vdia'rneters 'posi'- ti'oned concentrically with 'the positioning 'spin'- dles '93 tc receive the Vprojecting edges 'of the tesist'ance elements '25, 26, 21 'and 28, respectively, of 'the `potentiometer unit when the potentiweter unit is moved successively from one station 'to the other to clean successive rsistante elernents. The slip ring 39 associated with the /sis'tance element being 'cleaned is 'adapted to 'egag'e the upper surface 94 'of the supporting plate to support the eleineiit being cleaned in a 'predeterinirred vertical 'relation to the supporting plate. At each station, (Figs. 3, 4, 5 and 6) the upper side ci the supporting plate is also refined with annular depressions or -g'i'cov'es '99-99 'to provide clearance for the three setsl of resistance elements and slip rings not involved i'iithe cleanling operation. arcuate recesses itu, itil,4 m2 and |03 Yare formed in the underneath sid f the plates 15, 16, 11 and 18, respectively, arid intrsect the annular grooves 95, 86, 9 1 and 98, respecuveiy, to provide slots m5, los, m1 and las in the plates.

`Rotary scratch brushes im, m, ligand lis t into the recesses |68, IUI, |62 and |83, rspetively, of the supporting entes is, 16', 11' and js and engageA the respective resistance eleine'its 25, 26', 2T and 28 when the potentiometer unit psition'ed at the Stations 45, 46, 41 and 48, respectively. The axes of the scratch brushes ||0` to Ha and the centerline or the notches mt to its are located at various distances from the aires f the spindles 52, which distances crrespod to the radial distances between the resistance elmeuts 25g-2t and the axis of trie potentiometer unit.

The adjustabie supporting plates" ift-ifiV are adjusted by-v means of the supporting and clahping screws 84 and 90 to the proper position' relativeto the brushes so that when a potentiometer unit is' applied to the supporting platethe" pripneral surfacecf the rotary' brushes wili engage the edge' of the resistance' deci-eut and citan a vthe cleaning predetermined portion of thewire wound thereon. Itv will be apparent that when a potentiometer unit is positioned atany of the stations, as shown in Figs. 3-6, it will be supported on the surface 94 of the supporting plate by the slip ring 39 associated with the resistance element being cleaned and the slip ring controls the extenttowhich the resistance element projects into theslot in the supporting plate and limits the extent of the engagement of the resistance element with the rotary scratch brush associated therewith. fThe position fof the rotary scratch brush is sorelated tothe potentiometer unit at'each station during operation that it only engages the edge of the resistance element being cleaned and does not contact any other part of the potentiometer unit.

The rotary ybrushes H0, HI, H2 and H3 are secured to the ends of horizontal shafts ||5,

H6, |1 and I8, respectively, which are mounted in suitable bearings in bearing blocks ||20 secured to the shelf 60. The shafts H5 and H8 have keyed to one end thereof pulleys |24 and |25, respectively, and the shafts H6 and H1 have keyed thereto double pulleys |26 and |21, respectively. The shafts |5| I6 and the shafts H1-H8 are operatively Iconnected together by belts |29 and |30, respectively, and the shafts H6 and H1 are connected to a motor pulley |3| by `belts |32 and |33, respectively. The motor pulley |3| is mounted on a shaft |34 of a reversible driving motor 35 suitably mounted in the housing 44. The direction of the motor is controlled by forward and reverse control switches |31 and |38, respectively, By reversing the rotation of the brushes when cleaning the resistance elements, a better cleaning eiect is obtained and the bristles of the brushes are straightened.

An exhaust system is provided to carry away the material removed from the potentiometer during the :cleaning operation and comprises individual housings or casings (Figs. 2 and 10) surrounding the rotary scratch brushes and connected to and forming a part of an exhaust conduit MI mounted on the shelf and extending through the end wall 5| (Fig. 2). The exhaust conduit |4| may be connected to any suitable exhaust system. The upper open ends of the exhaust housings |40 are spaced from the supporting plates 15-18 and cooperate with telescoping tubular members M2 secured to the under side of the supporting plates.

After a potentiometer unit has been completely assembled and it is desired to clean the edges of the resistance elements therein, an operator may place the potentiometer unit over the spindle 92 at one of the stations as, for example, 45, and move the potentiometer unit downwardly into engagement with the supporting plate 15. The potentiometer unit is then supported on the surface 94 of plate 15 by the slip ring 39 `associated with the resistance element 25. The edge of the resistance element 25 is then properly positioned vertically in the groove 95 and contacts the peripheral surface of the rotating scratch brush H9 through the slot |05. The rotating scratch brush H6 will remove the -cement and other foreign material from the portion of wires of the resistance element 25 from which the insulation has been removed, and by rotating the potentiometer unit about the spindle 92 through one or more complete revolutions with the brush rotating in one direction and then rotate the potentiometer unit with the brush rotating in the as indicated in Fig. l. 1

reverse direction, the operator may effect the cleaning of the Contact surface of the resistance element 25. The potentiometer unit may then be removed from station 45 and applied to station 46 infa similar manner and rotated through one or more revolutions. At station .46, the potentiometer vunit will be supported by the slip ring 39 associated with the resistance element 26 and the resistance element 26 will be positioned in the annular groove 96 and will contact the rotating scratch brush Hlthrough the slot |06 and, as the resistance element 26 is rotated, -the lower edge thereof will be cleaned. Upon the completion of the cleaning of the resistance element 26, the potentiometer unit may be withdrawn from station 416 and applied to station 41, where the resistance element 21 maybe cleaned in a cleaning operation similar to that described for :cleaning the resistance elements 25 and 26, upon the completion of Vwhich the nal resistance element 28 may be cleaned in a similar manner by applying the unit to station 48 and rotating it through one or more complete revolutions.

What is claimed is:

1. An apparatus for cleaning arcuate resistance elements of an electrical device comprising a member for supporting said electrical device, means on the supporting member for positioning the electrical device for rotation about its axis, said supporting member having annular grooves therein for receiving the arcuate resistance elements projecting from the electrical device and a recess therein intersecting one of said grooves to form a slot through which a portion of a resistance element is accessible, a rotary scratch brush projecting into the recess to engage and clean a portion of the resistance element accessible through the slot, and means for rotating said brush.

2. An apparatus for cleaning the edge of arcuate resistance elements of a circular potentiometer unit comprising a plate for supporting a potentiometer unit thereon and having an annular groove on one side thereof for receiving the arcuate resistance element projecting from the potentiometer unit and a recess on the opposite side thereof intersecting said groove to form an arcuate slot through which a portion of the resistance element is accessible, a post on said supporting plate concentric with said groove for positioning a circular lpotentiometer unit yfor rotation about its axis and with the arcuate resistance element in said groove, a scratch brush mounted for rotation about a xed axis and projecting into the recess to engage and clean a portion of the resistance element accessible through the slot, and means for rotating said brush.

3. An apparatus for cleaning arcuate resistance elements of an electrical device comprising a frame, a supporting member pivotally connected at one end to the frame for supporting an electrical device thereon and having a circular groove in the upper portion thereof for receiving the edge portion of a circular resistance element of the electrical device and having a recess intersecting the groove to form an arcuate slot in the supporting member through which a portion of the resistance element is accessible, a spindle mounted on said supporting member in .concentric relation to the annular groove therein for positioning the electrical device for rotation about its axis on the supporting member with a portion of an arcuate resistance element of the electrical device in the slot in the supporting mem-ber, a rotatable scratch brush mounted on the frame and engage- JEROME E.. MARCUS. LAWRENCE B. WAL'IER.

Tkfe ifowi-'ng references are of r'ecor inthe ie 'of this patent:

TTS `'1T-"ATE"IST'IS`Y Numbei', 

